Patients with a common type of metal hip implant should have regular health checks.
Most people who have a metal-on-metal implant have well-functioning hips. They are thought to be at low risk of developing any serious problems.
Some metal-on-metal hip devices have been found to wear down more quickly in some patients.
This can cause damage and deterioration in the bone and tissue around the hip which medical checks will monitor.
Check-ups are a precautionary measure to reduce the small risk of complications. They are also used to monitor patients who have had the devices implanted for a long time.
What you should do if you have a hip implant
Metal-on-metal implants have been used in a minority of hip replacement surgeries. This may not affect you.
Consult your doctor if you're not sure what type of implant you have. They will discuss any concerns you may have about your hip.
If you do have a metal-on-metal implant, make sure you attend any follow-up appointments.
You should also be aware of the warning signs that could signal a problem.
The warning signs
You should contact your doctor if you have:
- pain in the groin, hip or leg
- swelling at or near the hip joint
- a limp or problems walking
- grinding or clunking from the joint
These symptoms don't necessarily mean your implant is failing. But they do need investigating.
Any changes in general health should also be reported, including:
- chest pain or shortness of breath
- numbness or weakness
- changes in vision or hearing
- feeling cold
- weight gain
Metal-on-metal implants feature a joint made of two metal surfaces:
- a metal "ball" that replaces the ball found at the top of the thigh bone (femur)
- a metal "cup" that acts like the socket found in the pelvis
Monitoring of implants
You should be checked regularly for the life of your metal-on-metal implant. You will have tests to measure levels of metal particles (ions) in your blood.
If you have these symptoms you may be investigated with MRI or ultrasound scans. If you don't have any symptoms you may still need a scan if the level of metal ions in your blood is rising.
The problems with metal-on-metal implants
Wear and tear
All hip implants wear down over time. The ball and cup slide against each other during movements such as walking and running.
Many people live the rest of their lives without needing a replacement implant. Some people may eventually need surgery to remove or replace its components.
Data suggests that certain types of metal-on-metal implants wear down faster than others.
Friction acts upon their surfaces. This can cause tiny metal particles to break off and enter the space around the implant.
People are thought to react differently to the presence of these metal particles. They can trigger inflammation and discomfort in the area around the implant for some.
If not caught early, this can cause damage. Deterioration in the bone and tissue surrounding the implant and joint can develop. This may cause the implant to become loose and cause painful symptoms. Further surgery is then required.
Metal ions in the bloodstream
The Health Products Regulatory Authority's (HPRA) recommendation is to check for the presence of metal ions in the bloodstream.
Ions are electrically charged molecules. Levels of ions in the bloodstream may show how much wear there is to the artificial hip. This applies particularly to the cobalt and chromium used in the surface of the implants.
These ions in the blood are not blood poisoning and do not lead to sepsis.
There has been no definitive link between ions from metal-on-metal implants and illness.
However there has been a link between high levels of metal ions in the bloodstream and illnesses. These include effects on the heart, nervous system and thyroid gland.